content: /**
   * Copyright (c) 2016-present, RxJava Contributors.
   *
   * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
   * compliance with the License. You may obtain a copy of the License at
   *
   * http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software distributed under the License is
   * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
   * the License for the specific language governing permissions and limitations under the License.
   */
  
  package io.reactivex.flowable.internal.operators;
  
  import java.util.concurrent.Callable;
  
  import org.reactivestreams.*;
  
  import hu.akarnokd.reactivestreams.extensions.RelaxedSubscriber;
  import io.reactivex.common.exceptions.Exceptions;
  import io.reactivex.common.functions.BiFunction;
  import io.reactivex.common.internal.functions.ObjectHelper;
  import io.reactivex.flowable.Flowable;
  import io.reactivex.flowable.internal.subscriptions.*;
  
  public final class FlowableReduceWith<T, R> extends AbstractFlowableWithUpstream<T, R> {
  
      final Callable<R> initialValueSupplier;
  
      final BiFunction<R, ? super T, R> reducer;
  
      public FlowableReduceWith(Flowable<T> source, Callable<R> initialValueSupplier, BiFunction<R, ? super T, R> reducer) {
          super(source);
          this.initialValueSupplier = initialValueSupplier;
          this.reducer = reducer;
      }
  
      @Override
      protected void subscribeActual(Subscriber<? super R> s) {
          R initialValue;
  
          try {
              initialValue = ObjectHelper.requireNonNull(initialValueSupplier.call(), "The initialValueSupplier returned a null value");
          } catch (Throwable ex) {
              Exceptions.throwIfFatal(ex);
              EmptySubscription.error(ex, s);
              return;
          }
  
          source.subscribe(new ReduceWithSubscriber<T, R>(s, initialValue, reducer));
      }
  
      static final class ReduceWithSubscriber<T, R> extends DeferredScalarSubscription<R>
      implements RelaxedSubscriber<T> {
  
          private static final long serialVersionUID = 7129356975009970557L;
  
          final BiFunction<R, ? super T, R> reducer;
  
          Subscription upstream;
  
          boolean done;
  
          ReduceWithSubscriber(Subscriber<? super R> actual, R value, BiFunction<R, ? super T, R> reducer) {
              super(actual);
              this.value = value;
              this.reducer = reducer;
          }
  
          @Override
          public void onNext(T t) {
              if (!done) {
                  try {
                      value = ObjectHelper.requireNonNull(reducer.apply(value, t), "The reducer returned a null value");
                  } catch (Throwable ex) {
                      Exceptions.throwIfFatal(ex);
                      onError(ex);
                  }
              }
          }
  
          @Override
          public void onError(Throwable t) {
              if (done) {
                  return;
              }
              done = true;
              value = null;
              actual.onError(t);
          }
  
          @Override
          public void onComplete() {
              if (done) {
                  return;
              }
              done = true;
              R v = value;
              value = null;
              complete(v);
          }
  
          @Override
          public void onSubscribe(Subscription s) {
              if (SubscriptionHelper.validate(upstream, s)) {
                  upstream = s;
  
                  actual.onSubscribe(this);
  
                  s.request(Long.MAX_VALUE);
              }
          }
  
          @Override
          public void cancel() {
              super.cancel();
              upstream.cancel();
          }
      }
  }
  